Bill Clinton’s visit to Colombia later this month will seal American backing for a plan to tackle drugs and guerrillas in its roughest area. But will it work?

PUERTO ASIS, a bustling town of some 80,000 people in the southern Colombian department of Putumayo, is a prosperous place by the standards of Colombia's southern lowlands, though all but its more important streets are unpaved. It is also a place that lives on its nerves. Though both the army and the police have bases in the town, right-wing paramilitaries walk around openly, in civilian clothes but with guns in their belts. In the surrounding jungle, power lies with the FARC guerrillas. And the whole area has become the most-watched front in Colombia's irregular wars.

In recent years, Putumayo has become home to some 60,000 hectares of coca, making it Latin America's largest single source of cocaine. Restoring the area to the control of the state is the immediate purpose for which the United States Congress in June agreed to grant $1.3 billion in military aid to President Andres Pastrana's government, as part of “Plan Colombia”, a $7.5 billion ragbag of schemes aimed at fighting drugs and supporting the country's faltering peace process.

To underline the United States' commitment to this plan, and to Mr Pastrana's embattled government, President Bill Clinton is due to visit Colombia on August 30th. But he will not set foot in Putumayo, nor even Bogota, Colombia's capital. Instead, for safety reasons, his visit will consist of just a few hours in Cartagena, a tourist resort on the north coast.

Most of the American aid will go to train and equip three new army “anti-narcotics” battalions. Based at Tres Esquinas, 145 kilometres (90 miles) from Puerto Asis, the prime task of these battalions, officials say, is to secure Putumayo, to enable police to attack its drug-processing laboratories and intensify their efforts to wipe out its coca plantations by spraying them with herbicides. The aim is to cut the supply of drugs—and of drug money to the FARC.

Certainly, a shift in Colombia's role in the drug industry has been a main cause of the FARC's expansion over the past decade. In the past, Colombia's drug gangs imported semi-processed cocaine from Peru and Bolivia. But under American pressure, coca ouput has plunged in those countries—only to move to Colombia. Taxing the coca harvest, and its processing, has provided the FARC with a ready source of revenue. Cut that, goes the official argument, and the FARC will become much more enthusiastic about the peace talks which have been proceeding desultorily for the past two years.

Yet in and around Puerto Asis, many people fear that, far from helping peace, Plan Colombia will exacerbate the war. It targets the poorest and weakest link in the drug industry. Little of the profit from cocaine filters back to those who grow coca, and process it into cocaine base. While a kilo of cocaine can fetch up to $100,000 on the streets of American cities, the price in Putumayo is about $1,000, points out Manuel Antonio Alzate, the mayor of Puerto Asis.

Yet coca still provides farmers with a better return than many other crops, largely because it finds ready buyers. “It's my only cash crop, since transporting my pineapples or plantain to market costs me more than the price they would fetch in Puerto Asis,” says Jose Sonza, who has a six-hectare (15-acre) farm carved out of the jungle.

Though some of the United States' aid is earmarked for schemes aimed at promoting alternatives to coca, there is little scope for such projects in Putumayo, where land and communications are poor; most goods and people are transported by river. Officials say that the plan is to provide alternatives in other areas for the farmers and labourers displaced from Putumayo's coca industry. But sceptics fear that many will end up swelling the ranks of the guerrillas. Ecuador's government, for its part, fears that the displaced, and the war, may flood over its largely unguarded border with Putumayo.

Neither would eradicating coca from Putumayo be fatal to either the drug industry or the FARC's finances. Coca can quickly be grown elsewhere. Any shortfall in the FARC's revenues from taxing the drug trade is likely to be offset by an increase in kidnapping and extortion. Reported kidnaps (more than half of which are estimated to be by the guerrillas) rose to 1,532 in the first six months of this year, up from 1,456 in the same period of 1999, according to Fundacion Pais Libre, a civic group. In April, the FARC issued a “law” demanding that all firms and individuals with assets of more than $1m pay a “tax” to them— or be “retained” (kidnapped).

Critics of Plan Colombia worry too about the aerial spraying of herbicides, the method used by the Colombian police to try and eradicate coca. The chemical spray poisons water sources and damages human health, according to people in Puerto Asis. Marta Cecilia Guapacha, the head nurse at the town's San Francisco hospital, says that she has treated many cases of poisoning, skin rashes and respiratory and eye problems which she believes to be caused by herbicides sprayed by police crop-dusting planes.

Unsurprisingly, both the paramilitaries and the FARC oppose coca eradication. “It will hurt only the poor peasant,” says “Comandante Halcon”(“Hawk”), a right-wing paramilitary leader who commands some 800 men in and around Puerto Asis.

But perhaps the biggest question facing Plan Colombia is what military response, if any, the three new battalions will meet when they head out from the Tres Esquinas base in their 60 helicopters. The answer may not come soon. Although one battalion finished its training last December, its helicopters have been sitting at another base, waiting for the aid to be approved. A group of 83 instructors from the United States' Special Forces arrived in Colombia this month to begin training the second battalion.

The FARC have denounced Plan Colombia as thinly-veiled intervention by the United States. The FARC's southern block, with some 3,000 troops mainly in Putumayo and Caqueta, claims to have prepared its defences, especially against the helicopters. The guerrillas are widely reckoned to have acquired hand-held anti-aircraft missiles. They are also reported to be handing out guns to the rural population in Putumayo. Meanwhile, the paramilitaries say they plan to step up their attacks against the FARC.

Caught between the guerrillas, the paramilitaries and the new army battalions, the inhabitants of Putumayo have reasons to fear for the future. “What can we do?” shrugs Mr Sonza. “The peasants are always the losers, and the drug traffickers continue to live unmolested in Miami.”